This invention relates to a marine cable burying method and a device therefor for burying communication or electric cables under marine beds in order to protect such cables from anchors of vessels or fishing tools.
In the prior art when a cable has to be buried under a marine bed, a burying device is generally tugged by a mother ship to lay and simultaneously bury the cable under the marine bed. More particularly, in this method, a cable is held within the burying device in advance of the mother ship, the burying device is lowered down onto the marine bed, and the burying device is tugged by the mother ship so that an excavation member provided on the burying device can dig a groove on the marine bed, whereby the cable is laid as well as buried in the groove at the same time. This method is superior in operability and efficiency when a cable is to be newly laid and buried under the marine bed; however, if a part of a cable which has been buried under the marine bed is broken, and, after being pulled up and repaired on the mother ship, is to be buried again, the method has such difficulties as requires a special mother ship with excellent operability to guide a burying device along the already buried portion of the cable. Further, since buried cables tend to take a tortuous rather than a straight course due to tidal current, it is extremely difficult to accurately detect the place where the repaired cable should be buried, unavoidably leaving a considerable portion thereof unburied.
Moreover, since this method necessitates the cable to be engaged within the burying device in advance on the mother ship and then lowered onto the marine bed by using a rope, the cable might be entangled with the rope due to the influence of tidal current, necessarily bringing the operation to a stop or causing the cable itself to be damaged by twisting or breaking.